Log Message:
databases/py-alembic: Import version 0.9.5 from pkgsrc-wip

Alembic is a database migrations tool written by the author of
SQLAlchemy. A migrations tool can emit ALTER statements to a database
in order to change the structure of tables and other constructs,
provides a system whereby "migration scripts" may be constructed; each
script indicates a particular series of steps that can "upgrade" a
target database to a new version, and optionally a series of steps
that can "downgrade" similarly, doing the same steps in reverse, and
allows the scripts to execute in some sequential manner.

Packaged by Kamel Ibn Aziz Derouiche and updated by me.